Manufacturing plants exist for the production of ethanol from grains, e.g., corn, and from sugars. Ethanol manufacturing is discussed in many sources, e.g., in The Alcohol Textbook, 4th Ed., ed. K. A. Jacques, et al., Nottingham University Press, 2003. Distillers grains (also referred to as distillers grains and solubles (DGS) or dry distillers grains (DDGS)) are a by-product of ethanol production. Distillers grains are a valuable by-product, as they are a major source of low-cost livestock feed. However, recently concerns have arisen due to the presence of antibiotics in distillers grains. The antibiotics in the distillers grains are generally present as a result of the use of antibiotics in the ethanol manufacturing process. Antibiotics such as penicillin and virginiamycin are used to control bacteria that compete with yeast during fermentation, converting sugar into lactic acid rather than ethanol. If restrictions on the sale or use of distillers grains are imposed due to concerns over antibiotic content, this will further damage the profit margins of ethanol producers, as well as depriving livestock farmers of a good source of livestock feed.
U.S. Patent Application No. 20060127999, “Process for producing ethanol from corn dry milling,” and U.S. Patent Application No. 20030077771, “Process for producing ethanol,” are each incorporated by reference herein in their entireties. In addition, U.S. Pat. No. 7,351,559 “Process for producing ethanol,” U.S. Pat. No. 7,074,603, “Process for producing ethanol from corn dry milling” and U.S. Pat. No. 6,509,180, “Process for producing ethanol” are each incorporated by reference herein in their entireties.